This project will demonstrate the use of direct methanol fuel cells (DMFC's) as power supplies for total artificial hearts (TAH) and permanent ventricular assist devices (VAD). Cardiovascular diseases are the leading cause of death in the U.S. In many cases a high quality life can be extended through heart replacement. Currently replacements means transplantation, but TAH's now under development offer another choice. In these devices the pump is powered by a rechargeable battery within the patient's body, which is recharged from an external power supply via an inductive coupling. The amount of energy stored in the external power supply limits the patient's mobility. A higher energy density power supply increases the amount of energy available, while reducing the device's size. This can be achieved with an external power supply utilizing a DMFC using aqueous methanol as fuel. Even low concentrations (<10%) of methanol, which are easily be handled non-flammable liquids, have energy densities over Wh/kg. A DMFC has the capability of serving as a safe, easily used, high energy density power supply. All of the key features of DMFC's have been demonstrated for other applications. This project will demonstrate a bench-top prototype power supply based on a DMFC as the prime energy source. The unit's effectiveness will be demonstrated by putting it through a series of cycles to simulate in vivo operation. PROPOSED COMMERCIAL APPLICATIONS: As the U.S. population ages, the number of lives that can be saved through cardiac replacement continues to increase. The number of donor organs limits the number of transplants that can be performed to less than 10% of the eligible patients. The total artificial heart expected to help close the gap, with tens of thousands of patients receiving artificial hearts each year. A practical artificial heart will require a more effective power supply than those available today, and this project will produce that power supply.